Lab practical bio 255 - Study guides, Class notes & Summaries

BIO 255 LAB PRACTICAL QUESTIONS AND ANSWERS WITH VERIFIED SOLUTIONS 2024

Selective and Differential plates: EMB: Gram negative rods grow Uses dyes eosin Y and methylene blue to inhibit Gram positive Gram negative rods are differentiated based on their ability of ferment lactose Slower fermenters: pink Medium fermentors: purple Fast fermentors: green Non-fermenters: light, translucent color MAC: Gram negative rods grow Uses crystal violet and bile salts to inhibit Gram positive Gram negative rods are differentiated based on their ability

Gram Stain Positive: Purple Negative: Pink 1. 4-5 layers 2. Crystal Violet 3. Iodine 4. Decolorizer 5. Safrin 2. Bacteria Shape Bacillus: rod shaped Coccus: round shape Spiral: spiral shaped 3. Catalase Test Hydrogen peroxide is toxic to bacteria and may be produced in the cell. Some bacteria contain catalase which can detoxify the hydrogen peroxide by converting it to water and gaseous oxygen. Positive: Bubbles Negative: Nothing happens Oxygen gas comprises the bubbles 4. Oxid...